Electric rotating machine refers to both generators and motors.
It is known that generator rotor windings can overheat because of various generator operation conditions and failure modes. If the temperature gets too high, insulation between the rotor windings can deteriorate leading to electric shortages.
The rotor of the electric rotating machine can be considered of any art such as salient pole, round rotor, squirrel cage, cylindrical, etc.
Prior art concentrates on:
estimating rotor temperature by measurement of rotor current, and controlling the temperature by varying the output load of the generator.
U.S. Pat. No. 8,967,857 B2 shows a temperature detection device that detects a temperature of a rotor of a motor by measuring rotor current.
U.S. Pat. No. 3,358,208 shows a method for controlling temperature rise in rotor windings by varying the output load.
US 2012/0133313 A1 describes a generator provided with a rotor temperature rise estimation device.
U.S. Pat. No. 8,482,238 B2 describes a system and method for estimating a generator rotor temperature in an electric drive machine.